Dispensing consistent, controllable, measured amounts of fluids such as adhesives, epoxies, lubricants, etc. at an assembly plant workstation is a long-standing problem facing manufacturers concerned with precision product assembly and business efficiency. As can be imagined, it is imperative that the optimum amount of fluid be dispensed if a quality good is to be produced. If too little fluid is dispensed, the product might be unsafe to use as designed. If too much fluid is dispensed, the product might be unsightly, messy, or unsafe; further, wasted fluid results in significant cost inefficiencies.
One solution to this problem is to provide a handheld applicator having a reservoir of fluid and attached to a source of the driving force needed to extrude the fluid. Use of a medical syringe as a reservoir and of a pressure-driven piston to provide the driving force on the fluid to be extruded are known in the art. The extant devices most similar to this invention are the syringe pump and the pneumatic pressure-driven fluid dispenser.
A syringe pump is a medical device that continuously introduces a fluid into an intravenous tube. These devices usually employ a gravity-fed tube attached to a reservoir (usually an intravenous bag or bottle) and a motor-driven pump that regulates the flow of fluid via a cam that alternately compresses and releases the tube.
A pneumatic pressure-driven fluid dispenser has a medical syringe used to store and apply the fluid to be dispensed attached to a control unit, which control unit in turn is attached to a compressed air supply (usually "shop air"). Fluid is dispensed when a controlled burst of pneumatic pressure depresses the syringe plunger a specific distance. However, neither of these devices reads on the presently claimed invention.
A major drawback of these conventional dispensers designed to extrude a precise volume of a fluid, such as industrial adhesives and the like, is that the "dosage" of fluid to be extruded cannot be controlled as precisely as desired.
In addition to enabling precise volumetric control, the ideal fluid dispenser should be an unobtrusive component in an assembly line workstation. It should conveniently be in reach of the worker, yet not impede the assembly process. Further, because of the significant physical and economic costs associated with repetitive motion syndrome (a.k.a. "carpal tunnel syndrome"), it is desirable that the fluid dispenser have an ergonomic design to minimize the incidence in assembly workers of injuries due to this syndrome.
The present invention provides an elegant solution to all of these problems.